Welding unit for motor car wheels

ABSTRACT

A welding unit for motorcar wheels has a pair of interchangeably mounted welding heads on a horizontal rail for selective alignment with an elevatable and rotatable support for the wheel. The head has a plurality of angularly equispaced electrode-wire feed devices for welding each of the spokes of the wheel but driven by a common motor.

United States Patent Dobosan et al.

[54] WELDING UNIT FOR MOTOR CAR WHEELS [72] Inventors: Valerio Dobosan,Brasov; Nicolae Cascaval, Orasul Sacele, both of Romania [73] Assignee:Uzina de Autocamioane Steagul Rosu Brasov Str. Poienelor, Brasov,Romania [22] Filed: Jan. 4, 1971 [21] Appl. No.: 103,677

[52] US. Cl. ..219/125 R, 219/60 A [51] Int. Cl. ..B23k 9/12 [58] Fieldof Search ..219/l24, 125 R, 126, 60 A, 219/60 R, 61, 127,137, 130, 87,76

[56] References Cited UNITED STATES PATENTS 1,886,503 11/1932 Shockey..219/124 1451 Nov. 14, 1972 3,062,950 11/1962 Chyle ..219/127 3,119,53611/1964 Berkely ..219/13o x 2,745,935

5/1956 Powley ..2l9/l24 X Primary Examiner-R. F. Staubly AssistantExaminer-L. A. Schutzman Attorney-Karl F. Ross [57] ABSTRACT A weldingunit for motorcar wheels has a pair of interchangeably mounted weldingheads on a horizontal rail for selective alignment with an elevatableand rotatable support for the wheel. The head has a plurality ofangularly equispaced electrode-wire feed devices for welding each of thespokes of the wheel but driven bya common motor.

10 Claims, 2 Drawing Eigt res WELDING UNIT FOR MOTOR CAR WHEELS FIELD OFTHE INVENTION BACKGROUND OF THE INVENTION In attempts to automate theproduction of wheels for automotive vehicles, the generally cylindricalfelly or rim is welded automatically to the central portion or hub at aplurality of angularly equispaced spokes along an'annular seam from theinterior of the wheel disk. Of course, external welds may also beprovided and to some degree at least hand-welding has been replaced byautomatic or machine welding.

In most machine-welding systems, a single electrode wire is fed to theweld seam while the workpiece is rotated or the head is rotated to carrythe weld seam completely around the wheel. It has also been proposed toprovide a number of welding heads for forming individual welds orsegments of the complete weld seam, but these arrangements are massive,complex and prone to breakdown.

Single-wire systems have the disadvantage that they are relatively slowand cannot adequately be integrated into a mass-production line.Finally, with respect to such prior mechanisms, it should be noted thatconventional welding heads are generally not capable of welding seams ata location deep within the wheel and hence cannot be used for weldingtorque wheels and other wheels of considerable rim width or wheel depth.

Furthermore, it is frequently desirable to provide a protective gas forthe welding process, i.e., a nonoxidizing or antioxidizing gas such ascarbon dioxide, helium, nitrogen or another oxygen-excluding gas with acarbon-dioxide medium. However, the welding guides or forward elementsof each of the multiple heads are subjected to high temperatures andspattered molten metals so that the heads must be removed for repair orreplacement of various parts. In conventional arrangements, thisrequires shutdown of the production line or at least the diversion ofthe wheelsto be welded from the normal production line.

OBJECTS OF THE INVENTION It is the principal object of the presentinvention to provide an improved apparatus for welding annular bodies.

It is another object of this invention to provide an apparatus for thewelding of automotive vehicle wheels which is free from thedisadvantages discussed above.

An object of the invention is also to be found in the provision of arelatively low-cost, simple and readily operable apparatus for thehigh-speed welding of internal seams.

Yet a further object of the invention is to provide a welding apparatusof the class described which, when requiring repair or maintenance, doesnot cause breakdown of the production line.

SUMMARY OF THE INVENTION The above and other objects of the inventionare attained in accordance with out invention which provides anapparatus for welding internal seams having a welding head axiallyspaced from a workpiece support or table, the head being provided with anumber of angularly equispaced electrode-wire guides, equal in numberand orientation to the spokes to be welded. The holder of the weldinghead also carries respective feed means associated with each of theguides for advancing a respective electrode wire therethrough and acommon drive means for all of these feed mechanisms. Means is providedfor relatively displacing the head and the support axially, preferablyby advancing the support in the direction of the head which is fixedwith regard to axial displacement.

According to a more specific feature of this invention, the head iscarried by a rail and can be locked thereto in alignment withthe.support, but is movable along thisrail to allow a similar second head tobe positioned thereon in alignment with the support. This allows thefirst head to undergo maintenance and repair while the second headmaintains the welding operation, thereby preventing interruption of theproduction line.

Yet another feature of the invention resides the provision of the commonfeed means as a central worm rotatable about the axis and meshing with aplurality of worm wheels, each being connected by respective gear meansto roller arrangements for advancing the electrode wire through theguides.

According to still another feature of this invention, the supportstructure is itself mounted by columns or posts upon the rails anddepends therefrom in the form of a housing within which the table isjournaled upon a shaft and is connected thereto by key means in the formof, for example, splines to permit axial displacement of the table whilethe latter is rotatably entrained by the shaft which is held againstaxial displacement in suitable bearing means. On the other hand, therail may be carried by the posts of the housing. A motor in this housingis connected via a clutch with the shaft for rotation of the turntableover a fraction of a revolution corresponding to the arc length of thespoke seam, while a yoke acts upon the table via thrust-bearing meansand, in turn, is displaced by piston-and-cylinder means located at thehousing to an extent determined by adjustable stops carried by thehousing. I

It will be apparent that the resulting structure is a simple and sturdyunit capable of simultaneously welding all of the spokes within thewheel. Of course, means may be provided to form the welds externally ofthe wheel as well. Advantageously, the table lies along a wheelproduction line and means can be provided in the housing to receive theelectrical circuitry for energizing the welding electrode. Above thehead, coils of electrode wire or rod may be provided. The welding wireor rods are fed generally radially outwardly by the feed means.

DESCRIPTION OF THE DRAWING The above and other objects, features andadvantages of the present invention will become more readily apparentfrom the following description, reference being made to the accompanyingdrawing in which:

FIG. 1 is a vertical elevational view, partly broken away, of anapparatus embodying the present invention; and

FIG. 2 is a detail view showing the electrode-feed means. v

SPECIFIC DESCRIPTION In the drawing, we show an apparatus for welding arim or felly B to a'wheel disk A at internal seams C along a pluralityof spokes D and E, two of which have been shown in dot-dash lines inFIG. 1. The external welds may also be provided with another array ofwelding heads but, since the external welding devices are not materialto the present invention, they have not been illustrated.

The apparatus comprises a rigid parallelopipedal body 1 constituting ahousing and extended by a pair of columns 2 from a rail 13. Within thehousing 1, there is provided the electrical circuitry 3 for thearc-welding system which may be connected to the continuously fed wireelectrode and to the workpiece by suitable conductors illustrated onlyin part. The columns 2 may be electrically conductive so that oneterminal of the arc-welding source may be connected to the rail 13.

Also within the housing 1, we provide a lifting and rotating assembly 4constituting the workpiece support and comprising the table 40supporting the disk A and having a cylindrical boss 4b for centering thedisk. A motor 5a mounted upon a speed-reducing transmission 5 issupported by pedestals 5c in the housing and has an output pulley 5bconnected by a belt 5d to the driven pulley 7a of a clutch 7. The outputmember 7b of this clutch is provided upon an upright shaft 6 which isjournaled in a bearing 60 on the housing 1. The clutch 7, 7a, 7b isoperated by a cam arrangement (not shown) and is designed to swing theworkpiece angularly through a distance corresponding to the arc lengthof the weld seam to be formed between the rim and each of the spokes.

The shaft 6 is splined to the shaft 8 which telescopingly fits over theshaft 6 and is axially shiftable thereon while being rotatably entrainedby shaft 6. The shaft 8 extends through an opening in the roof 1a of thehousing 1 and is formed at its lower end with a bronze sleeve 9 whichcan be engaged by a brush 9a shown in dot-dash lines for deliveringelectric current to the workpiece A E. The shaft is also formed at itsbottom end with a thrust bearing 11a in rolling contact with a collar 11forming swivels 11b for a plurality of piston rods a each receivedwithin a cylinder 10 articulated to the floor lb of the housing 1.

The pneumatic cylinders 10 are offset laterally from the lifting deviceand upon actuation elevate the shaft 8 and hence the workpiece A-E. Whenthe cylinders are depressurized, the workpiece is gradually lowered.Instead of a collar 11, moreover, a yoke extending around the shaft 6may be provided as the point of attack of the cylinders 10.

Depending from the roof 1a of the housing 1 are a number of adjustingdevices generally represented at 12 and consisting of sleeves 120 intowhich spindles 12b are threaded, the heads 12c forming adjustable stopsfor the yoke or collar 11. The stop arrangements 12 can be set toposition the seams at any desired distance from the welding wires F.

The rail 13 carries a pair of welding devices represented generally at14 and 14' and interchangeably positionable above the workpiece A E sothat, when one of the workpieces is undergoing maintenance or repair,the other may be operative and vice versa.

Each of the welding heads 14 and 14 comprises a carriage 30 on which aresupported reels 16 of welding wire (electrode wire) F, the reel supportshaving been omitted in the drawing for clarity. In addition, the rollingcarriage 30 is formed with a lock 15 which is threadedly received in aprojection 15a of the carriage and is engageable, upon rotation, withthe lower flange 13a of the rail to prevent further horizontaldisplacement of the head. A motor 17a is mounted in the carriage and isconnected by a speed-reducing transmission 17 with an input shaft 18,the latter, in turn, driving a worm 19 within a housing 14a upon whichthe welding wire guide members and gas nozzles 14b are mounted bytubular brackets 14c serving .to feed a protective gas, e.g., carbondioxide, into the region of the weld seam. The worm 19 drives aplurality of worm wheels 20 which, in turn, mesh with idler gears 22 andwire-feed wheels 21 to advance the welding wires F into juxtapositionwith the joint G'to be welded (FIG. 2).

Counterrollers 21a co-operate with the wheels 21 to advance the weldingwires. A respective guide and gas nozzle 14b is provided for each of theseams to be formed and, therefore, for each spoke of the finished wheel,along with a respective electrode-wire feed system and the correspondingreel. When the table 4 is lowered, it can be brought into horizontalalignment with a roller conveyor or track 24 which delivers the wheeldisk and the rim to the table.

OPERATION If is is assumed that the welding system 14' is undergoingnozzle replacement or other maintenance or repair, and welding system 14has been locked in place by member 15, successive wheel assemblies aredelivered by the roller conveyor 24 to the table 4. The latter is raisedto position eachwheel assembly upon the tableand juxtapose the joint Gwith the weld wire. The welding current is applied, motor 17a startedand motor 7, operated to simultaneously strike the welding arc, depositsweldment from the weld wire, advances the weld wire to compensate forconsumption of the weld material, and rotates the workpiece to form theweld along the entire arc of the wheel spoke associated with aparticular welding electrode.

Hence, the seam is formed simultaneously at all of the spokes. As soonas the seam at each spoke has been completed, the cam operates clutch 7to terminate rotation of the table whereupon the latter may be loweredand the welded wheel deposited upon a downstream roller track while anew wheel assembly is positioned at the table.

It will be apparent that the system of the present invention has theadvantage that it permits welding with high efiiciency for internal anddeep seams as well as for any external seams which may be necessary, itpermits production to be continued even after a breakdown of one of thewelding heads, it produces all of the seam welds simultaneously with asingle motive force for advancing the electrodes and controlling theelectrode wires, and it enables replacement of parts of the welding headwithout difficulty.

The improvement described and illustrated is believed to admit of manymodifications within the ability of persons skilled in the art, all suchmodifications being considered within the spirit and scope of theinvention except as limited by the appended claims.

We claim: a

1. An apparatus for welding internal seams of a concave workpiece,comprising:

a support for said workpiece centered on an axis and having an internalseam to be welded, said workpiece being open'axially in a directionaway'from said support; 1

p a welding head spaced along said axis from said sup port in saiddirection and aligned with said support, said head including:

a holder operatively aligned with said support along said axis,

a plurality of electrode-wire guides adapted to be trained at said seam,said guides being mounted on said holder and angularly spaced about saidaxis and directed outwardly from said axis in the opposite direction atsaid seam,

respective feed means on said holder associated with each of said guidesfor advancing an electride wire vtherethrough generally in a radialplane of said axis, and

common drive means on said holder for operating all of said feed means;and

means for relatively displacing said head and said support axially tojuxtapose the electrode wires with said seam.

2. The apparatus defined in claim 1 wherein each of said feed meansincludes at least one feed roller engaging the respective electrode wireand rotatable for advancing same, said common drive means including aworm lying along said axis, a motor for driving said worm, a pluralityof worm wheels meshing with said worm and axially spaced about said axisand respective gear means for operatively connecting each of said wormwheel with the respective roller.

3. The apparatus defined in claim 2 wherein said support is rotatableabout said axis and said head is fixed with respect to movement alongsaid axis, said means for relatively displacing said head and saidsupport including means for axially shifting said support, saidapparatus further comprising a second motor operatively connected withsaid support for rotating same about said I I v 4. The apparatus definedin claim 3 wherein said workpiece is a motor-vehicle wheel disk having agenerally cylindrical portion open axially in the direction of said headand a spoke portion adapted to be welded to said cylindrical portion ata plurality of angularly spaced spokes, the number of said electrodewireguides being equal to the number of such spokes and said guides beingangularly equispaced corresponding to said spokes.

5. The apparatus defined in claim 4, further comprising a horizontalrail carrying said head, said head depending from said rail and beingshiftable therealong out of alignment with said support, said apparatusincluding a further similar head alignable with said support to saidrail.

6. The apparatus defined in claim 5 wherein said suprt in ludes alatform receivin said wheel disk and i tatable about aid axis, a shaftlying along said axis and keyed to said table while being rotatable bysaid second motor, said means for axially shifting said supportincluding a yoke adapted to entrain said table vertically while beingjournaled relatively thereto, and

' fluid-responsive piston-and-cylinder means connected with said yokefor axially shifting same.

7. The apparatus defined in claim 6, further comprising a clutchinterposed between said second motor and said shaft.

8. The apparatus defined in claim 7, further comprising means forsuspending said support from said rail.

9. The apparatus defined in claim 8, further comprising a housingenclosing said shaft, said yoke, said second motor and saidpiston-and-cylinder means, and adjustable stop means on said housingengageable with said yoke for limiting the axial displacement of saidtable.

10. The apparatus defined in claim 9, further comprising means forsurrounding said electrode wires with a nonoxidizing gas.

1. An apparatus for welding internal seams of a concave workpiece,comprising: a support for said workpiece centered on an axis and havingan internal seam to be welded, said workpiece being open axially in adirection away from said support; a welding head spaced along said axisfrom said support in said direction and aligned with said support, saidhead including: a holder operatively aligned with said support alongsaid axis, a plurality of electrode-wire guides adapted to be trained atsaid seam, said guides being mounted on said holder and angularly spacedabout said axis and directed outwardly from said axis in the oppositedirection at said seam, respective feed means on said holder associatedwith each of said guides for advancing an electride wire therethroughgenerally in a radial plane of said axis, and common drive means on saidholder for operating all of said feed means; and means for relativelydisplacing said head and said support axially to juxtapose the electrodewires with said seam.
 2. The apparatus defined in claim 1 wherein eachof said feed means includes at least one feed roller engaging therespective electrode wire and rotatable for advancing same, said commondrive means including a worm lying along said axis, a motor for drivingsaid worm, a plurality of worm wheels meshing with said worm and axiallyspaced about said axis and respective gear means for operativelyconnecting each of said worm wheel with the respective roller.
 3. Theapparatus defined in claim 2 wherein said support is rotatable aboutsaid axis and said head is fixed with respect to movement along saidaxis, said means for relatively displacing said head and said supportincluding means for axially shifting said support, said apparatusfurther comprising a second motor operatively connected with saidsupport for rotating same about said axis.
 4. The apparatus defined inclaim 3 wherein saId workpiece is a motor-vehicle wheel disk having agenerally cylindrical portion open axially in the direction of said headand a spoke portion adapted to be welded to said cylindrical portion ata plurality of angularly spaced spokes, the number of saidelectrode-wire guides being equal to the number of such spokes and saidguides being angularly equispaced corresponding to said spokes.
 5. Theapparatus defined in claim 4, further comprising a horizontal railcarrying said head, said head depending from said rail and beingshiftable therealong out of alignment with said support, said apparatusincluding a further similar head alignable with said support to saidrail.
 6. The apparatus defined in claim 5 wherein said support includesa platform receiving said wheel disk and rotatable about said axis, ashaft lying along said axis and keyed to said table while beingrotatable by said second motor, said means for axially shifting saidsupport including a yoke adapted to entrain said table vertically whilebeing journaled relatively thereto, and fluid-responsivepiston-and-cylinder means connected with said yoke for axially shiftingsame.
 7. The apparatus defined in claim 6, further comprising a clutchinterposed between said second motor and said shaft.
 8. The apparatusdefined in claim 7, further comprising means for suspending said supportfrom said rail.
 9. The apparatus defined in claim 8, further comprisinga housing enclosing said shaft, said yoke, said second motor and saidpiston-and-cylinder means, and adjustable stop means on said housingengageable with said yoke for limiting the axial displacement of saidtable.
 10. The apparatus defined in claim 9, further comprising meansfor surrounding said electrode wires with a nonoxidizing gas.